反应详情

温度

-15 °C

3.65 g (3R,5S)-5-Biphenyl-4-ylmethyl-3-methyl-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (3-a, R1=Boc) is added to toluene (20 ml). Sodium hydride (400 mg) is added to the mixture. The mixture is cooled to −15° C. 22 ml Potassium bis(trimethylsilyl)amide (0.5 M solution in toluene) is then added. The resulting mixture is then stirred for 1 h at −15° C. Phenylselenyl bromide (2.8 g) in toluene (20 ml) is then added to the mixture. The resulting mixture is stirred for 0.5 h at −15° C. The mixture is then poured into water and the phases are separated. The organic phase is concentrated under reduced pressure. Ethyl acetate (50 ml) and aqueous hydrogen peroxide (10 ml, 30%) is then added to the residue at ambient temperature. After 1 h of stirring, the phases are separated. The organic phase is washed with saturated sodium hydrogen carbonate solution, and then saturated sodium hydrogen sulfite solution, before being concentrated under reduced pressure. The residue is crystallised from isopropyl acetate/heptane (20 ml:5 ml) to afford (R)-5-biphenyl-4-ylmethyl-3-methyl-2-oxo-2,5-dihydro-pyrrole-1-carboxylic acid tert-butyl ester (4a, R1=Boc). 1H NMR (DMSO): 1.56 (9H), 1.66 (3H), 3.02 (1H), 3.32 (1H), 4.75 (1H), 7.04 (1H), 7.18 (2H), 7.36 (1H), 7.46 (2H), 7.60 (2H), 7.66 (2H).

1. stirringThe resulting mixture is stirred for 0.5 h at −15° C
2. customthe phases are separated
3. concentrationThe organic phase is concentrated under reduced pressure
4. additionEthyl acetate (50 ml) and aqueous hydrogen peroxide (10 ml, 30%) is then added to the residue at ambient temperature
5. stirringAfter 1 h of stirring
6. customthe phases are separated
7. washThe organic phase is washed with saturated sodium hydrogen carbonate solution
8. concentrationsaturated sodium hydrogen sulfite solution, before being concentrated under reduced pressure
9. customThe residue is crystallised from isopropyl acetate/heptane (20 ml:5 ml)